INDUCTANCE AND CAPACITY 



351 



move in the guides, r. Four equally spaced brass rods, 5 mm. 

 in diameter and having screw threads cut on their upper ends, 

 are firmly attached to ring R l} and pass upward, with ample 

 clearances, through holes in the ring R%. Four equally spaced 

 vertical rods are attached to #2- Each plate is pierced with 

 eight holes, four of them 5 mm. and four 12 mm. in diameter. 

 The holes are so placed that they accommodate the eight vertical 

 rods. 



A B 



FIG. 208. Secondary air condenser. 



The condenser is built up by first putting on a member of 

 electrode 2. The smaller holes in this plate just fit the rods 

 $2 and the larger holes allow ample clearances for the rods Si. 

 Distance pieces of the proper diameter and of a length sufficient 

 to give a 2-mm. air space between the plates are then slipped 

 over the rods Si. They rest on the ring Ri and pass with ample 

 clearances through the holes in R 2 ; on these four distance pieces 

 rests the first plate of electrode 1. Distance pieces 8 mm. in 

 diameter and 5 mm. long are then slipped over the rods Sz and 

 rest on top of the first plate of electrode 2; the second plate of 

 electrode 2 is then slipped on and rests on the top of the distance 

 pieces, and so on. 



